From a quick search myself on the forum (what a horrible image capcha they use!) the host file solution is to solve a DNS problem they seem to have sometimes. they also seem to have had a lot of problems with spam (and porn) posts so they have banned some IPs.
If they are banning your IP and changing it when at home doesn't work then all I can suggest is emailing them again.
don't suppose you can get to the contact form can you?
http://www.videoredo....Board/sendmessage.php